Scientists first identified the BA.2 Omicron in India and South Africa in late December 2021. Since then, it has spread to several countries, including the United States, the United Kingdom, and Israel.
The subvariant virus has also spread rapidly in Denmark, increasing from 20% of all COVID-19 cases in the country in week 52 of 2021 to 45% in the second week of 2022.
Despite its rapid spread in the country, initial analyses show no difference in hospitalizations between the BA.2 subvariant and the original form of Omicron, also known as BA.1.
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Studies, however, are still ongoing to understand the infectiousness of BA.2, alongside how effective vaccines are against it.
While BA.2 is not currently a “variant of concern,” public health officials in the U.K. have taken enough interest in its spread to designate it as a “variant under investigation.”
To understand more about the emerging subvariant, Medical News Today spoke with six experts in public health, immunology, and infectious diseases.
Rapid spread
“Omicron has three main [subvariants] — BA.1, BA.2, and BA.3 — according to the World Health Organization (WHO),” Dr. Donald C. Vinh, associate professor in the Department of Medicine at McGill University, Canada, told MNT.
“Up until now, the overwhelmingly large majority of all Omicron cases has been BA.1. However, in some places, the BA.2 has emerged and has spread faster than BA.1,” he went on to note.
“This sister variant, which is still Omicron, is interesting because it seems to be displacing Omicron in certain parts of the world,“ Dr. Amesh A. Adalja, senior scholar at Johns Hopkins Center for Health Security, told MNT. “There is speculation that it may be more transmissible than its sibling.”
How the fast spread of the BA.2 subvariant may affect public health is still under investigation.
“The Omicron SARS-CoV-2 variant has been interesting to scientists because of its comparatively (i) higher number of mutations, which […] allow it to partially evade people’s immune response; (ii) higher transmissibility and pathogenicity, i.e., its greater ability to infect and cause disease; and (iii) lower virulence, i.e., its lower ability to cause severe disease,” Dr. Richard Reithinger, Ph.D., vice president of global health at RTI International, explained.
“The big question for newly identified variants and subvariants such as omicron BA.2 is how these above three characteristics vary from the original SARS-CoV-2 virus [variant] or the Omicron variant and why.”
– Dr. Richard Reithinger, Ph.D.
“If some countries are now reporting a surge in the proportion of BA.2 subvariant infections, is it because the additional mutations make it more transmissible or allow it to evade the immune response more easily than the other Omicron subvariants? Will BA.2 result in the same clinical pathology as the Omicron parent variant (B.1.1.529) and subvariants (BA.1 and BA.3)? Also, how do current therapeutic options and vaccines fare against BA.2?”
According to Dr. Reithinger, these are some of the questions that public health experts must take into consideration while keeping this subvariant under observation.
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